Describing what a child learns from the very first exposure to a new word is a critical step in understanding the process of word learning as a whole. This project is designed to assess the types of partial word knowledge (e.g., syntactic knowledge, semantic knowledge) that develop from a single exposure to a new word in reading by children with language-learning disabilities (LLD). In children with typically developing language, it is possible to detect some types of partial word knowledge from one exposure; a critical next step is the examination of the types of partial word knowledge that develop from a single exposure in children with LLD. In addition, an evaluation is needed of the roles of language and memory abilities in the development of vocabulary knowledge in children with LLD, compared to children with typically developing language. The specific aims of the proposed project are the detection of the types of partial word knowledge growth from one exposure for children with LLD, the comparison of the partial word knowledge types that develop for children with LLD and their peers with typical language development, and the examination of the roles of language and memory abilities in partial word knowledge growth. The performance of children with LLD will be compared to that of children similar in age and children similar in reading comprehension abilities. Using a pre/posttest design, children will read stories containing unfamiliar nouns and verbs, and partial word knowledge growth will be assessed. This study will contribute to an understanding of the types of partial word knowledge children with LLD demonstrate and retain in the beginning of the word learning process, relative to peers with typically developing language. The long-term objective of this research program is to elucidate differences in the overall processes of word knowledge growth, from LLD children's first encounter to their eventual mastery of a word's meaning. Focus on the specific processes of word learning is essential from a public health perspective, because it enables development of intervention procedures for school-age children with LLD. If, for example, these children are found to have difficulty acquiring a particular type of word knowledge, such as part of speech, vocabulary intervention can be designed to focus on this aspect of word knowledge, in particular.